The present invention relates to a fluid bearing for journalling rotating shafts, in particular to a hydrostatic and/or aerostatic radial and/or axial load carrying bearings.
Fluid bearings are commonly employed to journal high speed rotary shafts such as yarn spinning or twisting spindles. In general, such bearings comprise an outer shell or housing in which one or more compression pockets are distributed uniformly about the axis of the shaft and into which a fluid under pressure is supplied. In these bearings, wherein the pressure medium is supplied by one pump, it is essential to provide throtting means or valve means to control the flow of fluid into the compartments in order to ensure the proper stability of the bearing. Different types of construction are known wherein these throtting means are integrated into the bearing itself.
Of the so called laminar (steady flow) throtting means the most common type comprises the use of a capillary tube valve. The drawback of this type of valve lies in the tolerance of the inner diameter of small capillary tubes. With the same length of tubes, the variances between inner diameters produces different hydraulic or aerostatic resistance. Since the resistance produced by capillary tubes is in a ratio to the inner radius of the tube approximating the "fourth power," it is disadvantageous that the fluctuation of the resistance is very great. Moreover, a pressure tight sealing connection of the capillary tube to the bearing compression compartment, is most difficult to obtain.
In addition to the use of capillary tubes, slot throtting means, integrated into the bearing, have also become known. These slot throttles are formed by the space between two surfaces of the fixed housing running normal to the axis of the shaft. While such constructions are effective the valve means formed therein have the drawback that the narrow flow apertures forming the throttling means readily become fouled so that frequent breakdown occurs during the operation of the bearing. It will of course be realized that this same drawback exists in the use of capillary tubes, since it is virtually impossible to provide a fluid media perfectly free of certain impurities.
It is the object of the present invention to provide a fluid bearing of the type described which overcomes the difficulties and drawbacks of the prior art.
It is a further object of the present invention to provide a fluid bearing employing either fluid or air media in which the throttling gaps or means are reliably prevented from fouling.
It is a further object of the present invention to provide a fluid bearing system in which an improved construction forming the throttling or valving means is provided, integrated totally within the bearing itself.
It is a further object of the present invention to provide a fluid bearing system having superior load capacity and rigidity for axial and/or radial load conditions.
The foregoing objects, other objects, and numerous advantages will be apparent from the following disclosure.